This longer collar was designed for use on MK12 Mod 1 rifles. It has an internal step that interfaces with a step in MK12 barrels that prevents rearward movement. The set screw, typically positioned on the bottom prevents rotation.
| UPC | |
| MFG | Allen Engineering |
| MODEL | MK12 MOD 1 SPR Collar |
| TITLE | Allen Engineering MK12 MOD 1 SPR Collar |